【作者】 王小康；

【导师】 黄健萌；

【作者基本信息】 福州大学 ， 机械工程（专业学位）， 2023， 硕士

【摘要】 高速开关阀以连续开关控制替代阀口开度节流控制,可极大降低节流损失、提高抗污染能力、实现液压系统数字化和高可靠性控制,是数字液压技术发展的关键。然而,单电磁铁驱动结构仅能做到开启关闭过程单一可控,且传统PWM驱动方案不足以充分发挥高速开关阀性能,实现更高频地开关。针对以上问题,本文提出双电磁铁结构高速开关阀,并基于相位-复合调制策略优化现有驱动方式。具体内容如下:首先,针对阀口开关过程难以完全受控的问题,提出双电磁铁分时吸引阀芯动作的高速开关阀结构,实现开启关闭过程均可控;对比常见软磁材料的饱和、剩余磁感应强度与矫顽力,选择综合性能较优的1J22铁铬合金作为磁性元件材料;为建立准确的系统数学与仿真模型,设计电磁铁线圈匝数、工作气隙、阀芯尺寸、行程等结构参数。其次,根据能量传递路径,建立双电磁铁高速开关阀系统的电场、磁场、机械、液压多物理场耦合数学模型与AMEsim仿真模型;基于数学模型,获取开关响应时间对频率及可控占空比的影响规律,揭示开关频率受限的根本原因;分析电磁铁线圈电流特征点与阀芯位置的对应关系,揭示特征点的存在机理与一致性原则,并提出基于开关电流双特征点检测响应时间的方法。然后,针对传统PWM驱动下开关频率受限的问题,基于仿真模型,分析幅值、相位、双极性及占空比调制的PWM驱动下双电磁铁高速开关阀频响特性,获取最大开关频率在单信号幅值变化下呈指数分布、在开关信号相位差以及双极性信号占空比变化下均呈近似正态分布的变化规律,围绕分析结果提出基于相位-占空比调制的双极性PWM优化方案,通过相位-占空比复合调制策略进一步提高PWM驱动下的开关频率。最后,搭建双电磁铁高速开关阀特性试验平台,开发基于Arduino的驱动控制系统和基于NI Lab VIEW的数据采集系统,设计频响特性测试与试验对比方案,通过电流特征点获取响应时间,结果表明:双电流检测相对误差在2.0%左右,验证该方法的准确性;通过测试可控占空比范围以及最大开关频率,获取最佳复合调制驱动方案,结果表明:对比未经调制的单、双极性PWM驱动方式,响应时间减少24.7%～42.4%、最大开关频率提高15.2%～51.0%、可控占空比范围提高14.3%～166.7%,验证该复合调制策略的有效性。本文创新性提出双电磁铁分时吸引阀芯动作的高速开关阀结构,解决单一电磁铁难以实现开关全程可控的问题;提出基于开关电流双特征点检测响应时间的方法,解决特征点不易得时响应时间难以检测的问题;提出通过相位-占空比调制同步优化开关信号相位差与占空比组合的策略,改善现有驱动方案,实现PWM驱动下开关频率突破瓶颈。更多还原

【Abstract】 Replacing the throttle control of valve opening with continuous switch control for high-speed on-off valves can greatly reduce throttle losses,improve pollution resistance,and achieve digital and high reliability control of hydraulic systems.This is the key to the development of digital hydraulic technology.However,a single electromagnet drive structure can only achieve a single controllable opening and closing process,and traditional PWM drive schemes are not sufficient to fully utilize the performance of high-speed on-off valves and achieve high-frequency switching.In response to the above issues,this article proposes a dual electromagnet structure high-speed on-off valve and optimizes existing driving methods based on a phase composite modulation strategy.The specific content is as follows:Firstly,in response to the problem of difficulty in fully controlling the opening and closing process of the valve port,a high-speed on-off valve structure with dual electromagnets is proposed to attract the action of the valve core at different times,achieving controllable opening and closing processes;By comparing the saturation,residual magnetic induction strength,and coercive force of common soft magnetic materials,1J22 iron chromium alloy with better comprehensive performance is selected as the magnetic component material;To establish an accurate system mathematical and simulation model,design structural parameters such as the number of turns of the electromagnetic coil,working air gap,valve core size,and stroke.Secondly,based on the energy transfer path,establish a coupled mathematical model and AMEsim simulation model for the electric field,magnetic field,mechanical,and hydraulic multiphysics of the dual electromagnetic high-speed on-off valve system;Based on a mathematical model,obtain the influence of switch response time on frequency and controllable duty cycle,and reveal the root cause of switch frequency limitation;Analyze the corresponding relationship between the current characteristic points of the electromagnetic coil and the position of the valve core,reveal the existence mechanism and consistency principle of the characteristic points,and propose a method for detecting response time based on dual characteristic points of switching current.Then,aiming at the problem of limited switching frequency under the traditional PWM drive,based on the simulation model,the frequency response characteristics of dual solenoid high-speed on-off valve under the PWM drive of amplitude,phase,bipolar and duty cycle are analyzed,and the maximum switching frequency is exponentially distributed under the change of single signal amplitude,and is approximately normal distribution distributed under the change of switch signal phase difference and duty cycle of bipolar signal,Propose a bipolar PWM optimization scheme based on phase duty cycle modulation based on the analysis results,and further improve the switching frequency under PWM driving through a phase duty cycle composite modulation strategy.Finally,a dual electromagnetic high-speed on-off valve characteristic testing platform was built,and a drive control system based on Arduino and a data acquisition system based on NI Lab VIEW were developed.A frequency response characteristic testing and experimental comparison scheme was designed,and the response time was obtained through current characteristic points.The results showed that the relative error of dual current detection was around 2.0%,verifying the accuracy of this method;By testing the controllable duty cycle range and maximum switching frequency,the optimal composite modulation driving scheme was obtained.The results showed that compared with unmodulated single and bipolar PWM driving methods,the response time was reduced by 24.7%～42.4%,the maximum switching frequency was increased by 15.2%～51.0%,and the controllable duty cycle range was increased by14.3%～166.7%,verifying the effectiveness of the composite modulation strategy.This article innovatively proposes a high-speed on-off valve structure with dual electromagnets to attract the action of the valve core,solving the problem of a single electromagnet difficult to achieve full controllable switching;Propose a method for detecting response time based on dual feature points of switching current,to solve the problem of difficult detection of response time when feature points are not easily available;Propose a strategy to optimize the combination of phase difference and duty cycle of switch signals through phase duty cycle modulation synchronization,improve existing driving schemes,and achieve a breakthrough in switch frequency bottleneck under PWM driving.更多还原